Castor machine oils



. Patented Feb. 18 1936 UNITED STATES 2,031,405 cAsToa MACHINE OILS Arthur L. Blount, Palo's Verdcs Estates, CaliL, as-. signer to Union Oil Company of California, Los Angelcs, CaliL, a corporation of Californiav No Drawing. Ap lication July 22, 1933,

Serial '1 Claims.

The invention relates to thdpreparation of caster machine oils.

Castor machine oils in general are oils identifled in the trade by their high viscosity, and are 5 used mainly as lubricants in machinery, such as farm machinery, where high heat is not generated by friction. The viscosities of such lubricating oils range fremabout 100 seconds Saybelt Universal. at 100 F. to about 1000 seconds Saybolt Universal at 210 F. or even higher. Casdifferentials, and other moving parts of machinery, where it is desirable to employ oils 01. high stability.

Another object of this invention is to produce caster machine oils on which the factors of time and heat exert a minimum efiect, and which are homogeneous and do not break down and dissociate into their component parts.

A further object of the present invention is to produce caster machine oils which arenot soluble in water and have the ability to resist emulsification therewith.

In the past, caster machine oils have been prepared by intermixing mineral oils with'soaps of fatty acids obtained from vegetable or animal oils, or with soaps prepared from naphthenic selected so as to produce the desired qualities in the final product. Thus, caster machine o'ils composed of a mixture of a highly viscous fraction of mineral oil such as lubricating oil, and of metallic soaps such as aluminum soaps and par ticularly the eleates, stearates and naphthenates thereof, have been used where a lubricant of relatively high viscosity and stringines's was de- 55 oils and aluminum eleate soaps. However, even acids, both the mineral oils and the soaps being has the proper blending characteristics its volaoils containing the above aluminum naphthenate or stearate soaps may break down comparatively quickly. Such decomposition naturallyrenders them unsuitable as lubricants because of their H loss. of viscosity and homogeneity, both of these .5 qualities, as is well known, being necessary requirements of high grade. caster machine oils. 'I'hus,,mixtures produced at a high-temperature from a lubricating oil and an aluminum soap such as aluminum stearate, do not possess, even 10 in the preferred proportions the characteristics of. caster machine oils since atordinary temperatures they are of the type of colloidal gels and do not display the characteristic stringiness required of the diiferent grades of caster machine 'oil. As the result of experimental work it has been new discovered that caster machine oils having the desired characteristics, 1. e. stability to timev and heat, high, viscosity, and homogeneity, can be produced byusing' a suitable mineral oil and a metallic soap of a saturatedhigher fatty acid, such as aluminum stearate, palmitate or behenate,. and incorporating into thethus compounded oil a blending agent in which the mineral oil and the metallic soap used are both soluble.

The addition of these blending agents, which will be described more fully hereinbelow, has the property of changing the metallic soap and mineral oil mixture from the colloidal gel state to the colloidal sol condition at ordinary tempera- 80 tures, thus making possible the' production. of 'castor machine oils which di play tl'le desired stringiness at atmospheric temperatures.

It has been further discovered that the preferred blending agent or solvent should have a relatively low vapor pressure at ordinary temperatures in order'to avoid the less of the solvent by evaporation which would naturally cause a. change in the characteristics of. the, compounded oil. This excessive evaporation of solvent would 0 result in an oil which would have the qualities of one prepared without the addition of a solvent. Thus, while a mixture containing butyl alcohol tility is such that exposure results in the evaporation of saidalcohol, leaving a colloidal gel as a residue. Such a material is highly unsatisfactory as a caster machine oil, because of the loss of its stringiness, viscosity etc.

It has been discovered that a blending agent in the form of a polyhydroxy-alcohol having an other group in the molecule has a high'solvent power for the aluminum stearate or equivalent soaps aswell-as for the oils employed. The .in-'

corporation of such a blending agent was found I to prevent the rapid dissociation of the easier machine oils with its incidents of drop in viscosity, homogeneity, etc. Although several types of such hydroxy-ethers may be used as blending agents, best results can be obtained with those hydroxy ethers which, as stated above, have relatively low vapor pressures at ordinary temperatures.

Therefore, broadly stated, the invention resides in the preparation of high grade castor machine oils from an oil (vegetable, animal or mineral) and aluminum stearate, or other aluminum soap,

or a soap of similar metal, by means of a blending agent, especially a stabilizing blending agent. The invention further resides in the use of a hydroxyether as such blending agent, said blending agent being a solvent both for the oil and for the soap, to maintain the stability of the compounded castor machine oil for a. much longer period of time than usual, as well as to hinder the dissociation usually caused by the action of heat.

Considering the invention in greater detail, the castor machine oil is prepared from an oil and an aluminum soap by the introduction thereinto of one or more of the selected blending agents. The soap may be commercial aluminum stearate, chemically pure aluminum dior tri-stearate, commercial aluminum palmitate or behenate, or a stearate, palmitate or behenate soap of another equivalent metal. In fact, an aluminum soap or salt of any saturated higher fatty acid may be used, and is therefore considered to be an equivalent of aluminum stearate. The blending agent must be one which is soluble both in the soap and in the oil, and preferably should have a comparatively low .vapor pressure at normal temperatures, thus insuring against substantial evaporation of said blending agent.

The term aluminum stearate or aluminum stearate soap as used in this specification and hereinafter in the appended claims, refers to the aluminum soap or salt of stearic acid as it is produced commercially, that is aluminum distearate, which may contain small quantities of free stearic acid, aluminum monoand tristearates, and probably very small amounts of aluminum palmitates. Thus, the term is intended to include the ordinary commercial or technical grade of aluminum stearate. However, the term obviously also includes the chemically pure aluminum diand tri-stearates. The terms aluminum palmitateand aluminum behenatef I similarly refer both to the commercial grades of the two soaps mentioned herein and to the aluminum soaps or salts of the chemically pure palmitic and behenic acids. The terms also include aluminum soaps or salts of the commercial grades of said acids, which latter may also contain certain quantities of stearic acid. The commercial grades of behenic acid may be obtained by the exhaustive hydrogenation of ilsh oils, followed by hydrolysis cf the thus obtained glycerldes.

As stated previously, the blending agent or solvent should be chosen so that it may be soluble both in the oil and in the soap used in the preparation of the castor machine oil. An agent or solvent containing a hydroxyl group and an ether groupjn the same molecule will accomplish and fulfill these requirements. Such substances are the hydroxy-ethers, and all those hydroxy-ethers which possess the requisite low vapor pressure and solvent properties outlined above are suitable agents. It has been found that the desired properties are present in the ether derivatives of the lower poly-hydroxy-alcohols, and particularly the di-hydroxy-alcohols. The inventor has particularly found that he can obtain the best results by using the following solvents: mono-methyl, mono-ethyl and mono-butyl ethers of ethylene glycol as well as mono-methyl, mono-ethyl and mono-butyl ethers of di-ethylene glycol. A1-

' though all of the above ether derivatives of the lower poly-hydroxy-alcohols may be used as the blending agents, the mono-ethyl ether of diethylene glycol, the vapor pressure of which was found to be only 0.13 mm. of mercury at 20 C., and the mono-butyl ether of di-ethylene glycol, whose vapor pressure is only 0.05 mm. at 20 C., are particularly adaptable as solvents for the preparation of castor machine oils according to the present invention both due to their desirable solvent properties for the oil and soaps used and to their comparatively low vapor pressures at normal temperatures.

But a small amount of said desired blending agent is required to produce the desired results, i. e. the stability, high viscosity, homogeneity and clarity, of the compounded castor machine oils. Depending upon the characteristics of the ingredients compounded to produce the resultant castor machine oil, different quantities of the blending agent should be used. However, the quantity of blending agent should preferably be within well defined limits, the range being between about 0.1% and 5% of the amount of the neutral oil used. lhe quantity of the aluminum soap may also vary, the range being between about 1% and 5% of the total mixture.

As an illustration of the invention, a lubricating oil having a viscosity of approximately seconds Saybolt Universal at 100 F. was mixed with 4% of aluminum stearate at a temperature of 100 F., the temperature being then increased to about 285 F. with constant stirring to dissolve the aluminum stearate in the oil. mixture became homogeneous it was cooled to about 200 F. and 1.5% of mono-butyl ether of diethylene glycol, based on the weight of the oilsoap mixture, was added with thorough mixing.

The resulting castor machine oil had an initial viscosity of 441 seconds Saybolt Universal at 210 F. At the end of a 60 day standing at 78 F. in an open can this improved castor machine oil had a viscosity of 435 seconds Saybolt Universal at 210 F., or a viscosity drop of less than 1.4%. To compare with the ordinary castor machine oils produced ,heretofore, a representative heavy castor machine oil having an initial viscosity of 445 seconds Saybolt Universal at 210 F. was allowed to stand for 60 days under the same conditions as the above described sample of the castor machine oil prepared according to the present invention. At the expiration of this period the ordinary oil had a viscosity of only 345 seconds Saybolt Universal at 210 F. or a drop of about 22.5%.

A less viscous castor machine oil was prepared according to the present invention from a mixture of 97% of a lubricating oil of a. viscosity of 100 seconds Saybolt Universal at 100 F. and 3% by weight of aluminum stearate, to which 1.5% by weight of mono-butyl ether of di-ethylene glycol was added. This castor machine oil having an initial viscosity of 132 seconds Saybolt Universal at 210 F., showed at the end of sixty days a viscosity of 143 seconds Saybolt Universal, or a rise of about 8% as compared with a drop of 36% for similar castor machine oil produced-by the usual well known methods, the latter oil- 75 When the prepared according to the present invention.

Castor machine oils oizithe desired viscosity can be also produced by varying the character of the mineral oils used. Thus, for the preparation of a light castor machine oil, light oils such as kerosene may be used, while heavier oils such as crude oil or heavy lubricating oils may be employed for the production of heavy castor machine oils. For example, it has been found practical to use lubricating oils with viscosities ranging from 60 to as high as 600 seconds Sayboli; Universal at 100 F. However, it must not be taken that oils Within the limits given above are the only ones applicable for use in preparing castor machine oils under the present invention, since it is chvious that oils of even lower or higher viscosities may be found desirable in the production of various grades of the new compounded castor machine oils. Also, corresponding results may be obtained with animal or vegetable oils, or mixtures of these with each other or with mineral oil.

It is thus clearly seen that the incorporation of small amounts of a blending agent or solvent, such as mono-ethyl ether of ethylene glycol, mono-ethyl ether of di-ethylene glycol or monobutyl ether of di-ethylene glycol, into various mixtures of neutral oils and aluminum soaps of the saturated higher fatty acids produces very desirable advantages in the final product.

It is to be understood that the above disclosures are not to be considered as limiting but merely as illustrative of .the generic invention, and that many. variations may be made within the scope of the appended claims.

I claim: 1

1. A castor machine oil comprising, a mineral oil, 0.1% to 5.0% of a mono lower alkyl ether of glycol and 1.0% to 5% of the aluminum soap of a higher saturated fatty acid of the group consisting of stearic acid and palmitic acid and behenic acid.

2. A castor machine oil as claimed in claim 1 in which the soap is aluminum stearate.

3. A castor machine oil comprising, a mineral oil, 0.1% to 5.0% of the mono ethyl ether of diethylene glycol, and 1.0% to 5.0% of the aluminum soap of a higher saturated fatty acid of the group consisting of stearic acid, palmitic acid and behenic acid.

. mono-butyl ether of diethyleneglycol and the soap is aluminum stearate.

1 7. A castor machine oil comprising mineral oil blended with about 4% of aluminum stearate and 1.5% of mono-butyl ether of diethylene glycol.

' ARTHUR L. BLOUNT. 

